One method of making coffee includes passing heated water through coffee grinds in order to infuse the water with coffee flavour and aroma. A common type of coffee maker that employs this method is the so-called “drip-type” coffee maker.
Drip-type coffee makers comprise a water reservoir and a brew basket for receiving coffee grinds. A delivery tube or other water passage takes water from the water reservoir, through an in-line water heater, and delivers it to a spreader above coffee grinds in the brew basket. The heated water passes through the coffee grinds and in to a carafe, cup or other vessel. A one-way valve is positioned in the delivery tube between the water reservoir and in-line water heater to prevent heated water from returning to the water reservoir.
As the in-line water heater heats water from the reservoir the water expands in volume and creates considerable amount of steam pressure. Due to the present of the one-way valve the water is pushed out along the downstream portion of the delivery tube and dispenses through the spreader over the brew basket.
However, not all the water being pushed out of the spreader is fully heated to the desired optimum temperature owing to localized heating effect inside the heater. Partially heated water will flow into the brew basket through the spreader. The water must pass through the delivery tubes and the air gap between the spreader and brew basket before reaching the coffee grinds. During this time substantial heat can be lost from the water, particularly during the early stages of brewing when the delivery tubes and air gap have not had time to heat up.
Also, at the initial start of the brewing cycle an initial column of cold water inside the delivery tube downstream from the in-line water heater is pushed out, by this partially heated water, into the brew basket.
Thus, a problem with known coffeemakers is that the water temperature in the brew basket will always be lower during the initial stages of the brewing cycle. This lowers the temperature of the final coffee beverage and affects its quality.